Age- and Gender-Specific TSH Reference Intervals in People With No Obvious Thyroid Disease in Tayside, Scotland: The Thyroid Epidemiology, Audit, and Research Study (TEARS)

• Published in: The journal of clinical endocrinology and metabolism Vol. 98; no. 3; pp. 1147 - 1153
• Main Authors: Vadiveloo, Thenmalar, Donnan, Peter T., Murphy, Michael J., Leese, Graham P.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Oxford University Press 01.03.2013; Copyright by The Endocrine Society; Endocrine Society
• Subjects: Adult; Age; Age composition; Age Distribution; Aged; Aged, 80 and over; Autoantibodies - blood; Biological and medical sciences; Databases, Factual - statistics & numerical data; Diabetes; Diabetes mellitus; Diabetes Mellitus - blood; Diabetes Mellitus - epidemiology; Endocrinopathies; Epidemiology; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Gender; Glycoprotein Hormones, alpha Subunit - blood; Humans; Iodine; Male; Medical Audit - statistics & numerical data; Medical sciences; Middle Aged; Morbidity; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Patients; Population studies; Reference Values; Retrospective Studies; Scotland - epidemiology; Seroepidemiologic Studies; Sex Distribution; Thyroid Diseases; Thyroid Gland - physiology; Thyroid-stimulating hormone; Thyroid. Thyroid axis (diseases); Thyrotropin, beta Subunit - blood; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology; United Kingdom; Scotland; Great Britain; Europe; United Kingdom > UK; Endocrinopathy; Obesity; Endocrine gland; Nutrition; Tear; Reference; Nutrition disorder; Thyroid diseases; Sex; Metabolic diseases; Thyroid stimulating hormone; Thyroid gland; Epidemiology; Audit; Adenohypophyseal hormone; Scientific research; Age; Endocrinology; Nutritional status; Public health
• ISSN: 0021-972X; 1945-7197; 1945-7197
• DOI: 10.1210/jc.2012-3191

Objective:The aim of the study was to examine the association of tested TSH with age, gender, and diabetes in a large population-based cohort without evidence of thyroid disease.Design:Record-linkage technology was used retrospectively to identify people without evidence of thyroid disease in the general population of Tayside, Scotland, from July 1, 2003, to December 31, 2009.Cohort:All Tayside residents who had thyroid function tests performed were identified. Using a unique patient identifier, data linkage enabled a cohort without thyroid disease to be identified by excluding anyone with thyroid or antithyroid prescription, thyroid-related admission or surgery, treatment with radioactive iodine and/or positive thyroid antibodies. Cases below 18 years of age were also excluded.Outcome Measures:We measured TSH distribution among different age groups and by gender.Results:We identified the latest TSH measurements in 153127 people from the reference population after applying the exclusion criteria. There was a significant increase in median TSH (1.58 mU/L at 31–40 y to 1.86 mU/L at >90 y; P < .001) and 97.5th centile TSH (3.98 to 5.94 mU/L, respectively) with increasing age. The 2.5th centile decreased with age (0.51 to 0.31 mU/L). Patients with diabetes had marginally higher TSH concentration (1.80 vs 1.70 mU/L; P < .001).Conclusion:The use of these age-specific reference intervals for TSH, especially in those over 70 years old, would result in the reclassification of many TSH results from “abnormal” to “normal” (within the 95th centile reference interval) and avoid unnecessary treatment.